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Water Activity Meter


Water Activity Meter

Water activity (aW) is defined as the current volume and availability of free water in a sample and should not be directly compared with the water content (g water/ g substance). The water activity is given aW value and ranges between 0 (absolute dryness) and 1 (condensed humidity). Only this Water Activity Meter can possibly form the ideal medium for determining microbiological growth on the surface that influences the microbiological stability. Free water in products is jointly responsible for the growth of undesirable organisms such as bacteria or fungi, which produce toxins or other harmful substances.

For the determination of the aW-value the relative humidity in the surrounding air over the sample is measured. It is proportional to the aW-value. A meaningful aW-measurement (Water Activity Meter) can only be done if the sample shows a constant temperature during the measurement. The relative equilibrium humidity of a product, which is ascertained through its partial pressure of water vapor on the surface, depends on the chemical compound, temperature, water content, storage environment, absolute pressure and packing. Water Activity Meter is a quality Laboratory Device for the high precision determination of the aw-value of food, pharmaceutics, cosmetic etc.

Features Of Water Activity Meter
  • High accuracy and repeatability
  • Temperature controlled measuring chamber
  • Increased measurement speed
  • Measurement cell with saved calibration data
  • Intuitive and simple menu navigation
  • Modular expandability to multi-channel system

Chemical/Biochemical Effects of High/Low aW value Is
  • Microbiological stability (growth)
  • Chemical stability
  • Content of proteins and vitamins Color, taste and nutritional value
  • Stability of the compound and durability Storage and packing Sorption isotherm
  • The relation b/w water content and water activity is showing the sorption isotherm of a product.
  • Change in Temp will vary the aw-value at each humidity point.